Implantable devices for thermal therapy and related methods

ABSTRACT

Methods and devices are disclosed herein that generally involve applying thermal therapy to tissue (e.g., localized cooling or heating of tissue), and in particular applying thermal therapy to the spinal canal, tissue disposed within the spinal canal, and/or nerve roots extending from the spinal canal. In some embodiments, tissue can be cooled or heated by implanting a malleable or deformable thermal device in proximity to the targeted tissue. The thermal device can be left in place following surgery to facilitate application of post-surgical thermal therapy. In some embodiments, the thermal device can be removed post-surgery in a minimally- or non-invasive manner. The thermal device can be connectionless or can include penetrable regions, pre-attached tubing, or detachable connectors to facilitate application of cooling or heating means to the device. Methods are disclosed for utilizing thermal devices and for carrying out various treatment regimens that involve cooling or heating tissue using such devices.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.15/465,046, filed Mar. 21, 2017, which is a continuation of U.S.application Ser. No. 14/535,659, filed Nov. 7, 2014, which is acontinuation of U.S. application Ser. No. 14/276,265, filed May 13, 2014(now U.S. Pat. No. 8,911,486), which claims the benefit of U.S.Provisional Application No. 61/878,168, filed Sep. 16, 2013, each ofwhich is hereby incorporated by reference herein in its entirety.

FIELD

Implantable devices for applying thermal therapy and methods relatingthereto are disclosed herein.

BACKGROUND

According to the National Spinal Cord Injury Statistical Center, thereare more than 259,000 people living with a spinal cord injury in theUnited States. Traumatic spinal cord injury afflicts around 15,000people in the United States each year. Approximately 12,000 survive thecord injury with a neurological deficit, which is commonly a severe,disabling physical impairment and mental burden. Long-term care for cordinjuries costs an estimated $9.7 billion annually in the United States.

Application of certain degrees of hypothermia to a patient's spine andspinal cord after a spinal cord injury can lead to benefits, such as areduction of the metabolic demand of spinal cord cells, reduction ofedema, added tolerance to hypoxia/ischemia, and ultimately a reductionin spinal cord tissue damage or cell death. Realizing these benefitscould mean the difference between quadriplegia and being able to useone's arms. The use of a cooling effect for these purposes can bereferred to as therapeutic hypothermia.

Besides traumatic spinal cord injury, the spinal cord can be injured dueto surgical procedures such as abdominal aneurysm repair, wherein bloodflow to the spinal cord is reduced. This lack of blood flow, also knownas ischemia, can cause cellular damage to the spinal cord. Local coolingof the spinal cord can decrease the incidence of spinal cord injury inabdominal aneurysm surgery. Nerve roots or any member of the centralnervous system in the spine can also become damaged from trauma and/orsurgical insult, and can cause neurologic deficits and/or significantpatient pain. It will be appreciated that the spinal cord and nerves canbecome injured through any number of means.

Existing methods for cooling the spine involve systemic cooling of theentire body. Such treatments carry a number of disadvantages. For onething, systemic cooling techniques lack the ability to specificallytarget the injured tissue and, as a result, other unrelated tissue canbe damaged or destroyed by the cooling. Systemic cooling can also causea wide variety of side effects. In addition, the degree to which thebody can be cooled systemically is very limited, and it is difficult toprecisely control the degree to which the body is cooled in systemicapproaches. Body temperature changes using systemic techniques also tendto occur very slowly, which can undesirably delay administration of acooling effect to the injured tissue.

In some instances it can be desirable to apply localized heating ortherapeutic hyperthermia to a patient.

There is a continual need for improved methods and devices for applyingthermal therapy.

SUMMARY

Methods and devices are disclosed herein that generally involve applyingthermal therapy to tissue (e.g., localized cooling or heating oftissue), and in particular applying thermal therapy to the spinal canal,tissue disposed within the spinal canal, and/or nerve roots extendingfrom the spinal canal. In some embodiments, tissue can be cooled orheated by implanting a malleable or deformable thermal device inproximity to the targeted tissue. The thermal device can be left inplace following surgery to facilitate application of post-surgicalthermal therapy. In some embodiments, the thermal device can be removedpost-surgery in a minimally- or non-invasive manner. The thermal devicecan be connectionless or can include penetrable regions, pre-attachedtubing, or detachable connectors to facilitate application of cooling orheating means to the device. Methods are disclosed for utilizing thermaldevices and for carrying out various treatment regimens that involvecooling or heating tissue using such devices.

In some embodiments, a method of applying thermal therapy to tissueincludes forming a tissue opening in a patient to access a target sitewithin the patient, passing a thermal device through the tissue opening,placing the thermal device at the target site, closing the tissueopening with the thermal device at the target site, and after closingthe tissue opening, applying or continuing to apply thermal therapy tothe target site through the thermal device, wherein the thermal devicecomprises a malleable pad.

In some embodiments, a method of applying thermal therapy to tissueincludes forming a tissue opening in a patient to access a target sitewithin the patient, passing a thermal device through the tissue opening,placing the thermal device at the target site, closing the tissueopening with the thermal device at the target site, and after closingthe tissue opening, applying or continuing to apply thermal therapy tothe target site through the thermal device, wherein the thermal devicecomprises a connector having a plurality of exposed loops of fluidtubing extending therefrom, and wherein placing the thermal devicecomprises placing the loops across the target site.

In some embodiments, a system includes an implantable pad having anouter membrane that defines a cavity therein and that includes apenetrable region, a connector insertable through the penetrable region,the connector including a fluid inlet conduit and a fluid outlet conduitwhich are placed in fluid communication with the cavity when theconnector is inserted through the penetrable region, and a thermalsource coupled to the connector and configured to circulate heated orchilled fluid through a fluid path defined by the fluid inlet conduit,the cavity, and the fluid outlet conduit to apply thermal therapy toanatomy disposed in proximity to the pad.

In some embodiments, a system includes an implantable pad having anouter membrane that defines a cavity therein, a fluid inlet conduitextending from the pad and in fluid communication with the cavity, afluid outlet conduit extending from the pad and in fluid communicationwith the cavity, and a thermal source coupled to the fluid inlet conduitand the fluid outlet conduit and configured to circulate heated orchilled fluid through a fluid path defined by the fluid inlet conduit,the cavity, and the fluid outlet conduit to apply thermal therapy toanatomy disposed in proximity to the pad.

In some embodiments, a system includes an implantable pad having anouter membrane that defines a cavity therein and that includes a port,the port including a mating interface, a connector having a matinginterface configured to be selectively coupled to the mating interfaceof the port, the connector including a fluid inlet conduit and a fluidoutlet conduit which are placed in fluid communication with the cavitywhen the connector is coupled to the port, and a thermal source coupledto the connector and configured to circulate heated or chilled fluidthrough a fluid path defined by the fluid inlet conduit, the cavity, andthe fluid outlet conduit to apply thermal therapy to anatomy disposed inproximity to the pad.

In some embodiments, a system includes a connector that includes a fluidinlet conduit and a fluid outlet conduit extending therethrough, aplurality of exposed loops of tubing extending from a distal end of theconnector, each of said loops having a first end in fluid communicationwith the fluid inlet conduit and a second end in fluid communicationwith the fluid outlet conduit, and a thermal source coupled to theconnector and configured to circulate heated or chilled fluid through afluid path defined by the fluid inlet conduit, the plurality of loops oftubing, and the fluid outlet conduit to apply thermal therapy to anatomydisposed in proximity to the loops of tubing.

The present invention further provides methods, systems, and devices asclaimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be more fully understood from the following detaileddescription taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a schematic view of a system for applying thermal therapy;

FIG. 2 is a perspective view of an ellipsoid thermal device;

FIG. 3 is a perspective view of a pear-shaped thermal device;

FIG. 4 is a perspective view of a cylindrical thermal device;

FIG. 5 is a perspective view of a box-shaped thermal device;

FIG. 6 is a perspective view of a spherical thermal device;

FIG. 7 is a perspective view of a U-shaped thermal device;

FIG. 8 is a perspective view of a triangular thermal device;

FIG. 9 is a perspective view of a faceted pear-shaped thermal device;

FIG. 10 is a perspective view of a rectangular thermal device positionedover a patient's dura;

FIG. 11 is a perspective view of a cylindrical thermal device positionedover a patient's dura;

FIG. 12 is a perspective view of a rectangular thermal device positionedover multiple levels of a patient's spinal column;

FIG. 13 is a profile view of a thermal device with a recess forreceiving a portion of a patient's anatomy;

FIG. 14 is a perspective view of a cylindrical thermal device having acircular penetrable region;

FIG. 15 is a perspective view of a spherical thermal device having aplurality of circular penetrable regions;

FIG. 16 is a perspective view of a spherical thermal device having aplurality of ring-shaped penetrable regions;

FIG. 17 is a perspective view of an ellipsoid thermal device in whichthe entire exterior surface is a penetrable region;

FIG. 18 is a profile view of a connector for penetrating a penetrableregion of a thermal device;

FIG. 19 is an end view of the connector of FIG. 18;

FIG. 20 is a perspective view of the connector of FIG. 18;

FIG. 21 is a profile view of a connector for penetrating a penetrableregion of a thermal device;

FIG. 22 is an end view of the connector of FIG. 21;

FIG. 23 is a perspective view of the connector of FIG. 21;

FIG. 24 is a profile view of a connector with an embedded sensor;

FIG. 25 is a perspective view of a thermal device with pre-attachedtubing;

FIG. 26 is a perspective view of a thermal device with a port that canbe selectively coupled to a connector;

FIG. 27 is a perspective view of the thermal device of FIG. 26 with aconnector coupled to the port;

FIG. 28 is a perspective view of a thermal device with a connector thatextends into the interior of the device;

FIG. 29 is a profile view of a thermal device with a heat transferelement;

FIG. 30 is a profile view of a thermal device in a collapsedconfiguration;

FIG. 31 is a profile view of a thermal device in an expandedconfiguration;

FIG. 32 is a profile view of a thermal device having multipleconnections;

FIG. 33 is a perspective view of a thermal device with an internal fluidpathway;

FIG. 34 is a cross-sectional perspective view of a cylindrical thermaldevice with a gel-filled inner reservoir;

FIG. 35 is a cross-sectional perspective view of a rectangular thermaldevice with a gel-filled inner reservoir;

FIG. 36 is a perspective view of a thermal device with a tether;

FIG. 37 is a perspective view of a thermal device that is attachable toa patient's anatomy or to other devices or implants;

FIG. 38 is a perspective view of the thermal device of FIG. 37 coupledto a patient's vertebra by first and second bone fasteners;

FIG. 39 is a perspective view of a thermal device having through holesfor receiving fasteners;

FIG. 40 is a perspective view of a thermal device positioned over apatient's dura and attached to a spinal cross-connector.

FIG. 41 is a perspective view of a thermal device with embeddedwireframe hooks;

FIG. 42 is a perspective view of a thermal device having a plurality ofexposed loops of tubing;

FIG. 43 is a perspective view of a portion of the thermal device of FIG.42;

FIG. 44 is a profile view of the thermal device of FIG. 42 in anelongated insertion or removal configuration;

FIG. 45 is a profile view of the thermal device of FIG. 42 in aflattened therapeutic delivery configuration;

FIG. 46 is a perspective view of a rectangular thermal device positionedacross multiple levels of a patient's spinal column;

FIG. 47 is a profile view of the thermal device and spinal column ofFIG. 41;

FIG. 48 is a perspective view of a cylindrical thermal device positionedover a patient's dura;

FIG. 49 is a flow chart of an exemplary method of applying thermaltherapy; and

FIG. 50 is a flow chart of another exemplary method of applying thermaltherapy.

DETAILED DESCRIPTION

Methods and devices are disclosed herein that generally involve applyingthermal therapy to tissue (e.g., localized cooling or heating oftissue), and in particular applying thermal therapy to the spinal canal,tissue disposed within the spinal canal, and/or nerve roots extendingfrom the spinal canal. In some embodiments, tissue can be cooled orheated by implanting a malleable or deformable thermal device inproximity to the targeted tissue. The thermal device can be left inplace following surgery to facilitate application of post-surgicalthermal therapy. In some embodiments, the thermal device can be removedpost-surgery in a minimally- or non-invasive manner. The thermal devicecan be connectionless or can include penetrable regions, pre-attachedtubing, or detachable connectors to facilitate application of cooling orheating means to the device. Methods are disclosed for utilizing thermaldevices and for carrying out various treatment regimens that involvecooling or heating tissue using such devices.

Certain exemplary embodiments will now be described to provide anoverall understanding of the principles of the structure, function,manufacture, and use of the methods and devices disclosed herein. One ormore examples of these embodiments are illustrated in the accompanyingdrawings. Those skilled in the art will understand that the methods anddevices specifically described herein and illustrated in theaccompanying drawings are non-limiting exemplary embodiments and thatthe scope of the present invention is defined solely by the claims. Thefeatures illustrated or described in connection with one exemplaryembodiment can be combined with the features of other embodiments. Suchmodifications and variations are intended to be included within thescope of the present invention.

In the description that follows, reference is made primarily to treatingtissue in and around the spinal canal, including the spinal cord, but itwill be appreciated that the methods and devices disclosed herein canalso be used to treat tissue in virtually any part of a human or animalbody, including organs, joints (e.g., hips, knees, elbows, shoulders),the brain, the heart, etc. It will also be appreciated that the term“spinal tissue” as used herein can include the spinal cord itself, aswell as nerves and nerve roots extending therefrom through spaces in thespinal column, together the “spinal neuraxis,” as well as other portionsof the central nervous system.

Furthermore, while methods and devices for cooling tissue are primarilydisclosed herein, it will be appreciated that the same or similarmethods and devices can be used to heat tissue, e.g., for the purpose ofapplying localized therapeutic hyperthermia.

In some embodiments, methods of applying thermal therapy involve“implanting” a thermal device in the patient. As used herein,“implanting” the thermal device refers to leaving at least a portion ofthe thermal device in the patient after the initial surgical phase oftreatment is completed (e.g., by closing a tissue opening over theimplanted device while tubing or connectors associated therewith extendthrough the closed incision). Implanting the thermal device facilitatesdelivery of postoperative thermal therapy, optionally for an extendedtime period or in multiple sessions over a prolonged period, which canprovide unexpected benefits for the patient.

For example, peak edema typically does not subside until about three tofive days after a spinal cord injury is sustained. With an implantablesystem, therapeutic hypothermia can be delivered throughout this periodto minimize swelling-related damage to the patient's spinal cord. Theability to implant the thermal device also allows for the patient to beclosed immediately following decompression, stabilization, or othersurgery that may be performed in connection with implanting the device,yet still preserves the ability to apply thermal therapy for extendedtime periods. It is desirable to conclude the initial surgical phase oftreatment as soon as possible so as to reduce the patient's exposure topossible infection, reduce the amount of time the patient must be underanesthesia, reduce the cost of the surgery by reducing the amount oftime required of surgeons, operating staff, operating rooms, and otherresources, improve hospital throughput by freeing up resources to treatother patients, and so forth.

The thermal device can be left implanted for any amount of time (e.g.,at least about 1 hour, at least about 4 hours, at least about 12 hours,at least about 18 hours, at least about 24 hours, at least about 48hours, at least about 72 hours, at least about 5 days, at least about 7days, at least about 2 weeks, at least about 1 month, at least about 3months, at least about 6 months, at least about 1 year, at least about 5years, at least about 10 years, and/or permanently or indefinitely).

System

FIG. 1 illustrates an exemplary embodiment of a system 100 for applyingthermal therapy. The system 100 generally includes a thermal device 102and a source 104 configured to provide a cooling or heating means to thedevice 102. Delivery of the cooling or heating means can be regulated bya controller 106. The thermal device 102 can be an implantablecontainer, pouch, balloon, pad, sac, etc. that can be positioned inproximity to tissue that is to be cooled or heated. The thermal device102 can be placed in direct contact with the tissue to be cooled orheated, or can apply a cooling or heating effect to the tissue in anindirect manner, e.g., through intermediate tissue, implants, or otherstructures.

Exemplary tissue that can be cooled or heated using the thermal device102 includes the spinous process, the vertebral body, the pedicles, thelaminae, the spinal canal, the spinal canal contents (including thespinal cord), nerves (including those surrounding or extending to/fromthe spinal cord), vessels, and muscles. The spinal canal contentsinclude, for example, epidural space, dura mater, subdural space,arachnoid space, subarachnoid space, intrathecal space, cerebral spinalfluid, pia mater, spinal arteries and veins, vasocorona, vertebralvenous plexus, nerve roots, ligaments, and fatty tissue. It will beappreciated that there is symmetry as well as repetitive elements to avertebra and referral to an element of the vertebra can be taken to meanany one of symmetric or multiple elements. For example, when referringto a pedicle, it can be intended to mean any one of the two, or both,pedicles of the vertebra.

Cooling/Heating Means and Source

The thermal device 102 can provide a cooling or heating effect using anyof a number of different cooling or heating means or combinationsthereof. For example, the cooling means can include the expansion of gaswithin the thermal device 102 or the circulating of a chilled fluidthrough the thermal device 102. The term “fluid,” as used herein, refersto any flowable material or collection of materials, including liquids,gasses, and combinations thereof. In one embodiment, the thermal device102 receives a compressed gas which by expansion acts as a coolant inthe thermal device 102. The expansion of the gas causes the gas and thethermal device 102 around it to experience a rapid decrease intemperature. Typical gases for such an application include Nitrous Oxideand Carbon Dioxide, but it will be appreciated that there are a widevariety of gases that can be used, including gasses which, in compressedform, will be liquid.

In other embodiments, the thermal device 102 receives a chilled liquidas the cooling means which flows through cavities or channels of thethermal device, thereby decreasing the temperature of the thermaldevice. Typical chilled liquids include saline solutions, water, liquidnitrogen, and ethyl alcohol. It will be appreciated that any number offluids can be used as the cooling means, and that there are advantagesto using biologically safe fluids. In still other embodiments, thethermal device 102 can include a thermoelectric device, such as aPeltier device, which when a voltage or current is applied, at least aportion of the device experiences a reduction in temperature. Thethermal device 102 can also house an endothermic chemical reaction whichresults in the reduction of temperature of the contents of the thermaldevice 102 and of the thermal device 102 itself. In other embodiments,the thermal device 102 is pre-chilled prior to a cooling procedure. Itwill be appreciated by those skilled in the art that there are a varietyof means by which the thermal device 102 can be cooled.

The thermal source 104 can be external (e.g., extracorporeal), can beimplanted in the patient, and/or can be formed integrally with thethermal device 102. In implementations in which the cooling means is anexpanding gas, the thermal source 104 can be a tank of compressed gaswhich is released into the thermal device 102 through a cooling deliveryconduit. Once the compressed gas is in the thermal device 102, it can beexpanded through an expansion nozzle into an expansion chamber in thethermal device 102, causing a rapid decrease in temperature.Alternatively, or in addition, the thermal source 104 can include acompressor that compresses the gas. In some implementations, thedelivery of the cooling means from the tank of compressed gas isregulated with the control unit 106 to limit the amount of gas and thepressure at which it enters the thermal device 102 via the coolingdelivery conduit. The control unit 106 can be an adjustable valve on thetank, which can be manually controlled, mechanically controlled, orautomatically controlled by a computing device. In implementations inwhich the thermal source 104 includes a compressor, the control unit 106can control the degree to which the compressor compresses the gas, orthe pressure of the gas presented down the conduit. The regulation ofthe release of the gas can be managed manually or automatically, ineither case, based on established protocols, conditions of the patient,and/or detectable physiological characteristics of the patient orcharacteristics of the thermal device.

An additional conduit can also be provided to exhaust expanded gas fromthe expansion chamber of the thermal device 102. The exhaust conduit canexhaust the gas into the atmosphere, to a collection tank, or to acompressor which in turn re-compresses the gas for reuse. As discussedfurther below, the delivery conduit and the exhaust conduit can begenerally circular in cross-section, and can be formed from any of avariety of medical-grade tubing materials known in the art. The conduitscan be flexible or rigid, or can include rigid portions and flexibleportions.

In implementations in which the cooling means is a chilled fluid, thethermal source 104 can be or can include a chiller or other apparatusfor cooling and pumping fluid, and the cooling delivery conduit can be atube for delivering the chilled fluid to the thermal device 102. In thiscase, the exhaust conduit can be used to return or exhaust the chilledfluid from the thermal device 102 back to the thermal source 104, to acollection tank, or to a drain. In such an implementation, the controlunit 106 can control the volume rate of chilled fluid flow, the pressureof the chilled fluid delivery lines, and/or the temperature of thechilled fluid. It will be appreciated that components of the fluiddelivery and circulation system can be positioned on the exhaust side ofthe system rather than the source side (e.g., a pumping mechanism thatpulls the chilled fluid through the device 102, the delivery conduit,and the exhaust conduit rather than pushing it through).

In implementations in which the cooling means is a Peltier deviceembedded in the thermal device 102, the thermal source 104 can include apower supply that powers the Peltier device, and the cooling deliveryconduit can include electrical lines that supply electrical current fromthe power supply to the Peltier device. The delivery and exhaustconduits can also be used to remove heat generated by the Peltier devicefrom the thermal device 102.

Delivery of the cooling means can be regulated to achieve apredetermined cooling effect, such as a specific temperature at aspecific location. Delivery of the cooling means can also be regulatedsuch that a specific volume of the cooling means is delivered, forexample in cases where the cooling means includes a chilled liquid orexpandable gas. Delivery of the cooling means can also be regulatedbased on changes or lack of changes in physiological characteristics.For example, the regulation of the cooling means, and thus the intensityof cooling, can be determined by quantitative and qualitative sensory ormotor-evoked potential (SEP, MEP) observations. In this example, thecooling means is provided at a certain level until the patient's SEP/MEPresults begin to degrade, improve, or otherwise change, at which pointthe regulation of the cooling means can begin to reduce or increase thedelivery of the cooling means.

It will be appreciated that any number of physiological characteristicscan be used to regulate the intensity of the cooling means, includingbut not limited to: blood pressure, target-tissue temperature, specifictissue temperature (proximate to target tissue), rectal bodytemperature, venous blood temperature near or exiting target tissue,pulmonary conditions, cardiac conditions, sensory evoked potentials(SEPs, including somatosensory evoked potentials), motor-evokedpotentials (MEPs), intrathecal pressure, perfusion pressure, levels ofblood oxygen & glucose, ATP concentrations, and effectors ofexcitotoxicity, vasogenic edema, apoptosis, inflammation, and enzymaticresponses. A real-time qualitative or quantitative determination can bemade based on any of the listed physiological characteristics as to howthe cooling means should be regulated.

One or more sensors can also be included in the thermal device 102and/or implanted in or around the patient. The sensor can be atemperature sensor embedded in or on the thermal device 102 to sense thetemperature the device exhibits, where this sensed temperature can thenbe used to control the delivery of the cooling means to the thermaldevice 102. The sensor can be connected to the control unit 106 via oneor more sensor wires to provide a feedback loop of information to helpdetermine how much cooling means and/or what temperature cooling meansto deliver to the thermal device 102. Alternatively, or in addition, thesensor can be connected via sensor wires to a display, meter, dial, orother indicator providing some form of output data from the sensor thatcan allow one to manually regulate the delivery of the cooling means.The sensor can also be connectable wirelessly and a wireless link can beused instead of the sensor wires.

In one implementation, a first sensor is embedded into the thermaldevice 102 and provides temperature data of the thermal device 102 and asecond sensor is implanted in the intrathecal space of the spinal canalto measure temperature of cerebral spinal fluid. This temperature datacan be used to either manually or automatically regulate the delivery ofthe cooling means.

It will be appreciated that more than one sensor, more than one sensortype, and more than one sensor placement location can be usedsimultaneously and that the data gathered from the multiple sensors canbe used independently or in combination to determine how the delivery ofthe cooling means is regulated. Exemplary sensors that can be usedinclude temperature sensors (e.g., thermistors or thermocouples),pressure sensors, chemical sensors, electrical sensors, magneticsensors, and optical sensors. Other types of sensing, such as remotesensing, can be used that do not require the sensor itself to be placedwithin the patient—ultrasound, including Doppler measurements, andfunctional MRI, all can be used to sense physiological characteristicsthat can be used to control or regulate the delivery of the coolingmeans. The information measured by a sensor or sensors can be used tocontinually adjust the regulation of the delivery of the cooling meansin real time or almost real time. Alternatively, or in addition, thesensed information can be used for safety monitoring. The advantages ofusing a sensor or sensors, along with sensor wires or othercommunication means, will be appreciated though their use may not benecessary.

Thermal Devices

An exemplary thermal device 102 is shown in FIG. 2. As shown, the device102 is generally in the form pad that can be positioned adjacent to atarget region of a patient to apply thermal therapy thereto. The pad 102can have an ellipsoid or spheroid shape as shown in FIG. 2 or any of avariety of other shapes. For example, the pad 102 can have a pear shapeas shown in FIG. 3, a cylindrical shape as shown in FIG. 4, a box shapeas shown in FIG. 5, a spherical shape as shown in FIG. 6, a U-shape asshown in FIG. 7, a triangular shape as shown in FIG. 8, a faceted pearshape as shown in FIG. 9, etc. In some embodiments, the pad 102 can besized and shaped based on the anatomy that is targeted for thermaltherapy. For example, as shown in FIG. 10, the pad 102 can have asubstantially flat, rectangular shape with rounded corners and convexedges and can be sized to fit between the transverse processes 108 andcover the exposed dura or spinal cord after a single-level laminectomy.By way of further example, as shown in FIG. 11, the pad 102 can have asubstantially cylindrical shape and can be sized to fit through acylindrical tissue pathway in order to position a distal end surface ofthe pad over the dura or spinal cord. The pad 102 can be positioned incontact with or in close proximity to the dura surrounding the spinalcord. As shown in FIG. 12, the pad 102 can have an elongate,substantially flat, and rectangular shape with rounded corners and canbe sized to extend across multiple levels of the spinal column. The pad102 can be placed over the intact lamina between the transverse andspinous processes 108, 110 as shown, or can be placed directly over theexposed dura or spinal cord after a multi-level laminectomy. The pad 102can also be placed over one or more spinal implants, such that the pad102 covers the implants and/or is in direct contact with or in closeproximity to the implants. As shown in FIG. 13, the pad 102 can includea recess or hemi-cylindrical depression 112 in its distal end surfacesized to receive at least a portion of the patient's spinal cord. Itwill be appreciated that the pad 102 can have virtually any size orshape and that the size and shape can be selected based on variousfactors such as the anatomical location of the target site, the age,weight, species, or sex of the patient, the nature of the injury orcondition suffered by the patient, and the types of procedures to beperformed in conjunction with thermal therapy (e.g., laminectomy,vertebral fusion, and the like).

The thermal device 102 can be a homogenous block of material (e.g., agel or a solid), or can include an outer membrane that defines an innerreservoir. The inner reservoir can be filled with any of a variety ofmaterials or media, including gels or liquids such as saline. Themembrane and/or the reservoir media can be bio-absorbable. The reservoirmedia, or any fluid that is supplied to or circulated through thereservoir, can include a radiographic or magnetic tracer to allowdetection of media migration out of the device using known imagingsystems.

The device 102 can be rigid or can be resiliently or non-resilientlymalleable or deformable such that the device can be conformed to theanatomical structures to which it is applied. In particular, the device102 can include a malleable membrane configured to form a substantialnegative of the anatomy against which it is placed to maximize thecontact surface area between the membrane and the anatomy.

The device 102 can be formed from any of a variety of materials.Exemplary materials include Silicone, Polyethylene terephthalate (PET),Nylon, Polyethylene (PE), Polyurethane, Polyvinyl chloride (PVC), Latex,Titanium, Steel, Gold, Cobalt Chrome, and combinations thereof. Thedevice 102 can have any of a variety of dimensions. The device 102 canhave dimensions of 10 mm diameter.times.5 mm tall. The device 102 canhave dimensions of 20 mm diameter.times.20 mm tall. The device 102 canhave dimensions of 40 mm diameter.times.40 mm tall. The device 102 canhave dimensions of 40 mm diameter.times.70 mm tall. The device 102 canhave dimensions of 10 mm long.times.10 mm wide.times.3 mm tall. Thedevice 102 can have dimensions of 20 mm long.times.20 mm wide.times.3 mmtall. The device 102 can have dimensions of 30 mm long.times.10 mmwide.times.5 mm tall. The device 102 can have dimensions of 60 mmlong.times.15 mm wide.times.6 mm tall. The device 102 can havedimensions of 100 mm long.times.30 mm wide.times.15 mm tall. The device102 can have dimensions of 300 mm long.times.60 mm wide.times.30 mmtall. The device 102 can occupy a volume of at least about 0.3milliliters, at least about 0.4 milliliters, at least about 1.2milliliters, at least about 1.5 milliliters, at least about 5.4milliliters, at least about 6.3 milliliters, at least about 45milliliters, at least about 50.3 milliliters, at least about 88milliliters, or at least about 540 milliliters.

The device 102 can be at least partially radiopaque to facilitatevisualization using fluoroscopy or other radiation-based imagingtechniques. For example, the device 102 can include a radiopaquemembrane or can be filled or impregnated with radiopaque particles.

The device 102 can include one or more embedded sensors, including anyof the sensors described above, as well as passive RFID temperaturesensors which can be used to monitor the temperature of the device. Atleast a portion of the device 102 can allow transmission of infraredwavelengths to detect the temperature of the device using externalinfrared measurement devices. For example, the proximal-facing surfaceof the device 102, or the entire device, can be formed from a materialthat permits infrared radiation to pass. Various other external,non-contact ways of measuring temperature can also be employed.

In some embodiments, as shown for example in FIG. 2, the device 102 hasno external connections and instead serves as a passive heat sinkdevice. The device 102 can be pre-chilled (e.g., in an ice bath,refrigerated chamber, etc.) before being placed or implanted in thepatient. Alternatively, or in addition, the device 102 can be cooledwhile inside the body by an active thermal device disposed adjacentthereto (e.g., disposed outside the body).

It will be appreciated, however, that the device 102 can also includeone or more external connections, such as electrical leads for sensorsor a Peltier cooling device, or fluid conduits for addition, extraction,or circulation of fluid.

For example, the device 102 can include one or more penetrable areasthrough which a connector can be inserted to facilitate thermalregulation of the device. FIG. 14 illustrates an exemplary cylindricalthermal device 102 that includes a circular penetrable region 114 formedin its proximal-facing end surface. FIG. 15 illustrates an exemplaryspherical thermal device 102 that includes a plurality of circularpenetrable regions 114 formed in ring patterns about the outer surfaceof the device. FIG. 16 illustrates an exemplary spherical thermal device102 that includes a plurality of ring-shaped penetrable regions 114.FIG. 17 illustrates an exemplary ellipsoid or spheroid thermal device102 in which the entire exterior surface of the device is a penetrableregion 114.

The penetrable regions can be formed from a different material than thatused to form the remaining portions of device's outer membrane. Thepenetrable regions can also be formed form the same or similar material,but with a lower stiffness or durometer. In some embodiments, thepenetrable regions are formed from an elastomer such as silicone. Thepenetrable regions can be self-sealing, such that they are configured tomaintain a fluid-tight seal around a connector inserted therethroughand/or after a connector is removed therefrom. The area immediatelysurrounding the penetrable regions can be reinforced to prevent tearingduring insertion of a connector through the penetrable area.

FIGS. 18-20 illustrate an exemplary connector 116 that can be used withpenetrable thermal devices. As shown, the connector 116 generallyincludes an elongate cylindrical body 118 having one or more fluidlumens (e.g., a fluid inlet conduit 120 and a fluid outlet conduit 122)disposed therein. The connector 116 can be a solid cylindrical body inwhich the fluid lumens 120, 122 are defined. Alternatively, the body ofthe connector 116 can be a tubular sheath disposed around one or moreindependent fluid lumens. The distal tip 124 of the connector can beshaped to facilitate insertion of at least a portion of the connectorthrough a penetrable area of the thermal device 102. In the embodimentshown in FIGS. 18-20, the distal tip of the connector has a slash-cut orangled shape to define a sharpened tip. FIGS. 21-23 illustrate aconnector 116 in which the distal tip 124 is conically-shaped.Cylindrical bores 126 formed in the conical tip 124 form fluid pathwaysbetween the fluid lumens 120, 122 of the connector body and the exteriorof the tip. As shown in FIG. 24, the connector 116 can include anembedded temperature probe or other sensor 128 for detecting variousattributes of the environment in and around the distal tip of theconnector 116. Exemplary temperature sensors include a simple wirethermocouple. Various other sensors can also be included, such aspressure, pH, or any of the other sensor types disclosed herein. In someembodiments, the sensor 128 can be disposed within the fluid outletconduit 122 or in close proximity to the fluid outlet conduit, as thiscan be the most accurate location to measure certain parameters such astemperature. The connector 116 can be rigid or flexible, or can includeone or more rigid portions and one or more flexible portions.

In use, the connector 116 can be inserted through a penetrable area 114of the thermal device 102 to form a pathway between the thermal deviceand the thermal source 104 through which cooling or heating media can beconveyed.

Other connection mechanisms can be used instead of, or in addition to,the penetrable regions described above. For example, the thermal device102 can include integral or pre-attached tubing, or a port to which aconnector can be selectively coupled and decoupled.

FIG. 25 illustrates an exemplary thermal device 102 having pre-attachedor integrally-formed inlet and outlet conduits 120, 122. The conduits120, 122 can include embedded sensors, such as temperature sensors. Theconduits 120, 122 can also include a frangible seam portion to allow theconduits to be broken off or otherwise separated from the thermal device102. In some embodiments, at least a portion of the conduits 120, 122can be formed from a bioabsorbable material such that the conduits arenaturally separated from the thermal device 102 with time as they areabsorbed by the body.

FIG. 26 illustrates an exemplary thermal device 102 having a port 128 towhich a connector can be selectively coupled or decoupled. As shown inFIG. 27, the connector 130 can include inlet and outlet conduits 120,122 and a mating feature 132 to facilitate attachment of the connectorto the port 128 of the thermal device 102. Any of a variety of matingfeatures can be used for this purpose, including interferenceconnections, threaded connections, snap-fit connections, detents,latches, pins, compression fittings, and the like. In some embodiments,the mating features can provide a positive mechanical interlockingconnection. The connector 130 can also include various mechanisms fordisengaging the connector from the thermal device 102. For example, theconnector can include a rip-cord that, when pulled from outside thepatient, breaks a connection between the connector and the thermaldevice. The connector can also include any of a variety of embeddedsensors, including one or more temperature sensors. The port 128 can beself-sealing such that a fluid-tight seal is formed when the connector130 is disconnected from the thermal device 102. For example, the port128 can include a resilient flap that is deflected out of position whena connector 130 is coupled to the port to allow fluid flow into and outof the device. When the connector 130 is removed, the biased flap canautomatically return to its closed position, sealing off the port 128.As shown in FIG. 28, the mating feature 132 of the connector 130 can beset back from the distal end of the connector such that the connectorextends partially into the interior of the thermal device 102. As alsoshown in FIG. 28, the thermal device 102 can include one or moreinternal baffles or walls 134 to direct or guide fluid flow through thedevice. For example, the thermal device 102 can include a center baffle134 aligned with the connector interface such that, when the connector130 is mated to the thermal device, the fluid inlet conduit 120 isaligned with a first side of the baffle and the fluid outlet conduit 122is aligned with a second, opposite side of the baffle.

FIG. 29 illustrates a thermal device 102 that includes a heat transferelement 136. In the illustrated embodiment, the heat transfer element isdisposed across a distal end surface of the thermal device, though itwill be appreciated that any portion of the device can include a heattransfer element. The heat transfer element can be configured to enhancethe transfer of thermal energy between the thermal device and theabutting anatomy. The heat transfer element can be formed from amaterial having a high thermal conductivity, such as biocompatiblemetals or ceramics. In use, the distal end surface of the device, andthus the heat transfer element, can be positioned against the patient'sspinal cord, dura, or other treatment region. The heat transfer elementcan be shaped or contoured to match the target anatomy. For example, theheat transfer element can include a hemi-cylindrical groove or recesssized to receive a portion of the spinal cord.

As shown in FIGS. 30-31, the thermal device 102 can be partially orcompletely collapsible to facilitate insertion, removal, or adjustmentof the thermal device. For example, the thermal device 120 can beinserted into a target site within a patient in a first, collapsedconfiguration (shown in FIG. 30) and then fluid can be supplied to thedevice to transition the device to a second, expanded configuration(shown in FIG. 31). When removal of the thermal device is desired, or atany other appropriate time, the device can be partially or completelyevacuated of fluid to cause or allow the device to collapse back to thefirst configuration. The device can be configured to collapse radiallyas shown, such that a diameter of the collapsed device is less than thatof the device when in its expanded state. Alternatively, or in addition,the device can be configured to collapse into a flat disc, such that aheight of the collapsed device is less than that of the device when inits expanded state.

The thermal device 102 can also be rolled and unrolled to transition thedevice between collapsed and expanded configurations, respectively. Forexample, the device can include a resilient wireframe disposed orembedded therein that biases the device towards a rolled configurationin which at least one dimension of the device is reduced. Uponapplication of cooling fluid to the device, the bias of the wireframe isovercome and the device transitions to the expanded configuration. Whenremoval of the device is desired, or at any other desired time, fluidcan be extracted from the device to allow the bias of the wireframe toreturn the device to the collapsed configuration.

The thermal device can include a single connection or multipleconnections. For example, as shown in FIG. 32, the device 102 caninclude separate connections for delivering cooling means and removingcooling means. In the illustrated embodiment, the thermal device is asubstantially rectangular pad 102 with a fluid inlet conduit 120 at afirst end of the device and a fluid outlet conduit 122 at a second,opposite end of the device. The inlet and outlet conduits can be placedin fluid communication with the device via connectors inserted throughpenetrable regions, pre-attached or integral conduits, and/or connectorsconfigured to be selectively coupled and decoupled from one or moreports of the device. The device 102 can include an inner reservoir 138that occupies substantially the entire interior of the device, as shownin FIG. 32. Alternatively, the device 102 can include one or moredefined fluid pathways extending therethrough. FIG. 33 illustrates anexemplary fluid pathway 140 that is coiled or snaked through the deviceto ensure that fluid flows through a significant portion of the device.The fluid pathway can include one or more branches, with paths arrangedin any direction or pattern. The fluid paths can be contained within thebody of the device, or can be attached or coupled to an exterior surfaceof the device.

As shown in FIGS. 34 and 35, in embodiments in which the device 102includes an inner reservoir 138, the reservoir can be filled or at leastpartially filled with a gel or other substrate 142. In some embodiments,the cooling fluid can be circulated through the reservoir, and can flowthrough the gel 142 and/or over or across the gel. The gel can bebiocompatible and/or bioabsorbable. Exemplary gel materials includepolymers such as poly-L lactic acid (PLLA), polyglycolic acid (PGA),polylactic acid (PLA), and combinations thereof. The gel can act as aninternal heat sink and can allow the device to have a defined orsemi-rigid shape before fluid supply is initiated. In other words, thedevice can have a self-supported shape or dough-like quality to it whileimplanting and before fluid flow begins.

The thermal device 102 can also include one or more tethers tofacilitate positioning of the device, removal of the device from thesurgical site, or separation of a connector from the thermal device. Thedevice can include a plurality of tethers, which can be coupled tovarious points on the device. For example, the device can include firstand second tethers attached to opposed sides of the device to allow thedevice to be shifted laterally or longitudinally or to be rotated withinthe surgical site. As shown in FIG. 36, the tether 144 can be a smallgauge cord, wire, suture, or tube and can extend proximally from thethermal device 102 (e.g., to a point outside of the patient when thethermal device is implanted or positioned in the patient). Thepre-attached tubing or selectively attachable connectors described abovecan be used as tethers. In other words, the tubing or connectors can beconceptualized as tethers having embedded or integrated tubing tofacilitate media flow into and out of the thermal device. The tether canalso be embedded in or tied up with the tubing that supplies fluid tothe device, and the tether can be used to detach the tubing like a ripcord or grenade pin. Any of the techniques described above forseparating tubing or connectors from the thermal device (e.g.,bio-absorption, frangible portions, etc.) can be applied to make thetether removable from the device. The tether can include one or moreembedded sensors, including any of the sensors described above.

The thermal device can also include one or more attachment features forcoupling the thermal device to the patient's anatomy or to one or moreancillary devices (e.g., implants, stabilization hardware, and soforth). For example, as shown in FIG. 37, the device 102 can includelateral wings 146 with openings 148 formed therein through which afastener can be applied. As shown in FIG. 38, the wings 146 can beattached to bony tissue of the patient (e.g., vertebral bone) using bonescrews, pins, staples, hooks, spikes, or other fasteners 150. The wings146 can also be coupled to a spinal implant, for example by inserting atleast a portion of the implant through the opening 148. By way offurther example, as shown in FIG. 39, the device 102 can include throughholes 148 formed in the body of the device though which fasteners 150can be applied to attach the device to the patient's anatomy or one ormore ancillary devices. As yet another example, as shown in FIG. 40, thedevice 102 can include hooks, loops, or other connectors 152 forcoupling the device to ancillary devices such as spinal cross-connector154. While a cross-connector is shown, it will be appreciated that thehooks or loops can be sized, positioned, or otherwise configured toattach the device to any of a variety of devices, including spacers,bone screws, fixation rods, and other hardware. As shown in FIG. 41, thedevice 102 can include wings or tabs 146 with a malleable wireframe 156disposed therein. The wireframe can be bent to hook or clamp the deviceto patient anatomy or to an implant or other device. Any of a variety ofother techniques can be used to secure or couple the device, includingstandalone clamps, sutures, etc.

By coupling the device to the patient anatomy or other implanteddevices, the device can be maintained in a desired position ororientation within the patient for extended periods of time, includingwell after a surgical procedure for implanting the device is completed.

As shown in FIGS. 42-43, the thermal device 102 can include a pluralityof flexible or semi-flexible exposed tubular loops 158 coupled to aconnector 160. For example, a fluid inlet conduit 120 extending throughthe connector 160 can branch into a plurality of tubes 158 which extenddistally outside of the connector. The plurality of tubes 158 loop backand couple to a fluid outlet conduit 122 extending through the connector160. In some embodiments, the plurality of tubes can remain independentas they extend through the connector. In use, a chilled fluid can becirculated through a plurality of fluid loops defined by the tubes toapply a regional cooling effect to tissue against which the tubes arepositioned. As shown in FIG. 44, the tubes 158 can be positioned in loopshapes having a reduced lateral diameter and an enlarged longitudinaldiameter to facilitate insertion or removal of the device 102 through acylindrical tissue opening having a small radius. As shown in FIG. 45,the tubes 158 can be transitioned (e.g., by pushing the connector 160distally) to loop shapes having an enlarged lateral diameter and areduced longitudinal diameter to spread the cooling mesh defined by thetubes radially outward over a treatment site. The plurality of loops canthus collectively define an ellipsoid wireframe (e.g., a prolatespheroid as shown in FIG. 44 or an oblate spheroid as shown in FIG. 45).When it is desired to remove the implanted device 102, aproximally-directed pulling force can be applied to the connector 160 towithdraw the connector and bend the tubes 158 into the configurationshown in FIG. 44 such that they can be extracted through the tissueopening formerly occupied by the connector. This can advantageouslyallow for easy post-operative removal of the device in a non-invasive orminimally-invasive manner.

As noted above, the thermal device can include an inner reservoir orchamber. The chamber can house at least a portion of the elements,volumes, nozzles, fluid lumens, channels, paths, and so forth needed tosupport the cooling means. In implementations in which the cooling meansincludes expanding gas, the thermal device can include an expansionnozzle through which gas that has entered the thermal device via acooling delivery conduit expands. The gas is expanded into the chamber,from which it can be exhausted from the thermal device via an exhaustconduit. The expanded gas can be exhausted into the environment, into achamber or tank, or into a compressor which re-compresses it.

In implementations in which the cooling means is a chilled fluid, thefluid can be passed through the inner chamber of the thermal device todeliver a cooling effect thereto and to surrounding tissue. In someembodiments, the chamber can be in the form of a fluid lumen having afirst end coupled to a delivery conduit and a second end coupled to anexhaust conduit. The chamber/fluid lumen can optionally be coiled,snaked, or formed in some other tortuous, surface-area maximizing shapesuch that heat exchange to/from fluid that is directed through thechamber can be optimized. The fluid can also simply enter the chamberthrough a delivery conduit, reverse direction, and exit the thermaldevice through an exhaust conduit.

In implementations in which the cooling means is a Peltier device, thePeltier device can be embedded inside the thermal device and electricallines can be connected to the Peltier device internal to the thermaldevice. These electrical lines can extend from the thermal device to apower source and optionally a regulator of the cooling effect, which canregulate the voltage or current on the electrical lines. In someembodiments, the power source and/or regulator can be disposed on or inthe thermal device or in a separate implantable unit.

The thermal device can optionally include a plurality of thermal finsformed within the chamber. For example, the thermal fins can extendradially inward from an outer wall of the chamber. In use, an expandedgas or chilled fluid can circulate around and across the thermal fins,which can improve the thermal conduction from the cooling means to thethermal device, and thus to the target tissue. The thermal fins can alsoimprove the mechanical strength of the thermal device. It will beappreciated that the thermal fins can be oriented in a variety ofdirections and can take on a variety of shapes and sizes.

The delivery conduit can extend well into the chamber, terminating at alocation adjacent to a distal end of the chamber. The exhaust conduit,on the other hand, can terminate only a small distance into the chamber,adjacent to the proximal end thereof. With this relative positioning ofthe conduit outlets, fluid introduced through the delivery conduit mustflow through substantially the entire length of the chamber before beingremoved through the exhaust conduit. In this manner, the thermaltransfer between the fluid and the thermal device can be maximized andmore evenly distributed along the heat exchanging surfaces of thethermal device. In some embodiments, the chamber and/or the deliveryconduit can extend only along discrete portions of the device wherecooling is desired.

In some embodiments, the delivery conduit can be helically wound aroundthe perimeter of the chamber. This can advantageously improve thermaltransfer between the delivery conduit and the thermal device. Inaddition, the delivery conduit can act as an internal baffle, routingfluid released from the distal end of the delivery conduit along ahelical path back towards the exhaust conduit. Thus, thermal transfercan also be improved between fluid released from the delivery conduitand the thermal device.

Portions of the thermal device other than the regions to be placedagainst the target anatomy can be coated with a thermally insulatingmaterial, such that the cooling effect is focused at the target site,such that surrounding tissue is protected from the cooling effect, andsuch that a surgeon or other user holding the device is protected fromthe cooling effect. Exemplary thermally insulating materials includesilicone, which can be spray coated onto the device.

It will be appreciated that the devices and hardware described hereinare able to be produced using common practices known to those skilled inthe art of hardware manufacturing and specifically surgical devicemanufacturing.

Methods

The thermal devices disclosed herein can be used in any of a variety ofassociated methods. Various examples of such methods are describedbelow. It should be noted that any ordering of method steps implied bythe following is not to be construed as limiting the method toperforming the steps in that order. Rather, the various steps of each ofthe methods disclosed herein can be performed in any of a variety ofsequences. In addition, as the described methods are merely exemplaryembodiments, various other methods that include additional steps orinclude fewer steps are also within the scope of the present invention.Furthermore, two or more of the method steps can be performedsimultaneously.

Before beginning a surgical procedure, a surgical plan can be developed,for example using pre-operative imaging of the site that is targeted forthermal therapy (e.g., cooling and/or heating). A thermal device havingan appropriate type, size, shape, etc. can be selected as part of thesurgical plan, or can be selected in real-time during the actualsurgery. As detailed above, the particular thermal device to be used canbe selected based on a variety of factors.

Access to the target site can be obtained using various knowntechniques. For example, a tissue opening can be formed using an opensurgical technique (e.g., one in which skin, fat, muscle, connectivetissue, etc. overlying the surgical site is incised and retracted). Atissue opening can also be formed using a minimally-invasive surgicaltechnique (e.g., one in which a percutaneous access device is used toform a portal between the patient's skin surface and the target site).

Various steps can be performed to prepare the target site for thermaltherapy. For example, in the case of a traumatic spinal cord injury, adecompression procedure (e.g., partial or complete laminectomy) can beperformed at one or more vertebral levels. By way of further example,the site can be prepared by decorticating bone in the vicinity of thetarget site. Thus, in the case of a spinal procedure, the surfaces ofthe lamina, spinous process, and/or facets can be decorticated.

Various ancillary or related procedures can be performed at the targetsite before or after initiating thermal therapy. For example, a spinalfusion procedure or a procedure to install spinal stabilization hardwarecan be performed.

The steps involved in placing the thermal device and applying thermaltherapy therewith vary depending on the type of thermal device that isused.

In some embodiments, a connectionless thermal device (e.g., of the typeshown in FIG. 2) is pre-chilled or pre-heated and then placed on thetarget site (e.g., the exposed dura or spinal cord of the patient).Placement of the thermal device can include conforming the device to thetarget anatomy. Correct placement of the device can be verified visuallyor using fluoroscopy or other imaging techniques. Embedded sensors canbe used to monitor various parameters of the patient or operatingenvironment, and the thermal therapy can be modulated based on theoutput of the sensors. For example, if sensed temperature at the targetsite drops below a desired level, the thermal device can be lifted offof the target site or removed from the target site. On the other hand,if the sensed temperature at the target site rises above a desiredlevel, the thermal device can be removed and re-chilled, or can bereplaced with another pre-chilled thermal device. Once the desiredduration of thermal therapy is attained, the device can be removed fromthe target site and the tissue opening can be closed. An implantable,active thermal device can optionally be implanted prior to closing thetissue opening for chronic delivery of thermal therapy.

In some embodiments, a passive connectionless thermal device (with orwithout pre-chilling or pre-heating) is placed on the target site (e.g.,the exposed dura or spinal cord of the patient). Placement of thethermal device can include conforming the device to the target anatomy.Correct placement of the device can be verified visually or usingfluoroscopy or other imaging techniques. The passive thermal device canbe cooled by an active cooling system, which can be disposed external tothe patient. Exemplary active cooling systems include heat exchangers,fluid coils, Peltier devices, ice packs, etc. Embedded sensors can beused to monitor various parameters of the patient or operatingenvironment, and the thermal therapy can be modulated based on theoutput of the sensors. For example, if sensed temperature at the targetsite drops below a desired level, the active cooling applied through thethermal device can be reduced. On the other hand, if the sensedtemperature at the target site rises above a desired level, the activecooling applied through the thermal device can increased. Once thedesired duration of thermal therapy is attained, the device can beremoved from the target site and the tissue opening can be closed. Animplantable, active thermal device can optionally be implanted prior toclosing the tissue opening for chronic delivery of thermal therapy.

In some embodiments, a thermal device having one or more penetrableregions (e.g., of the type shown in FIGS. 14-17) is placed on the targetsite (e.g., the exposed dura or spinal cord of the patient). The devicecan be placed initially while in a collapsed, rolled-up, and/or deflatedconfiguration (e.g., through a minimally-invasive pathway). A connectorcan be inserted through a penetrable region of the device to allowapplication, removal, or circulation of cooling media before or afterthe device is placed at the target site. A single connector housinginlet and exhaust conduits can be used, or multiple connectors (e.g.,one for inlet and one for exhaust) can be inserted through the same ordifferent penetrable areas. In some embodiments, a single connectorhaving a single conduit can be used, in which case media application andremoval steps can be performed serially through the same lumen. If thedevice is initially placed in a collapsed configuration, fluid can bedelivered through a fluid inlet conduit of the connector to inflate thedevice to the desired size or shape.

Placement of the thermal device can include conforming the device to thetarget anatomy. Placement of the thermal device can also include pullingor otherwise manipulating one or more tethers extending from the deviceto adjust a position or orientation of the device. Correct placement ofthe device can be verified visually or using fluoroscopy or otherimaging techniques. Placement of the thermal device can also includeanchoring or clamping the device to the patient anatomy or to a device,implant, etc. at the target site (e.g., using attachment features likethose shown in FIGS. 37-41).

Thermal therapy can be applied through the device, for example bycirculating a chilled fluid through the device. The device can include areservoir filled with gel or some other substrate material, in whichcase the fluid can be circulated through the gel or substrate. Embeddedsensors can be used to monitor various parameters of the patient oroperating environment, and the thermal therapy can be modulated based onthe output of the sensors. For example, the temperature and/or flow rateof fluid circulated through the device can be adjusted to maintain adesired temperature. Where only intraoperative therapy is desired, thedevice can be removed once the desired duration of thermal therapy hasbeen applied and the tissue opening can be closed. Where postoperativetherapy is desired, the thermal device and one or more connectors can beleft in place and the tissue opening can be closed. The one or moreconnectors can be left exposed, extending through the closed tissueopening. The one or more connectors can also be left buried beneath thepatient's skin, where they are readily accessible in aminimally-invasive follow on procedure to conduct additional thermaltherapy or to remove the one or more connectors. In either case, theconnectors can be sutured or otherwise secured to prevent excessivemovement or inadvertent expulsion. Postoperative thermal therapy can bedelivered through the one or more connectors for an extended period, asdescribed in more detail below. When the capability to deliveradditional thermal therapy is no longer desired, the one or moreconnectors can be removed (e.g., by pulling them proximally to withdrawthem from the penetrable regions of the device). The thermal device canbe left implanted permanently, and can optionally be configured to bebioabsorbed by the patient over time. Alternatively, the thermal devicecan be removed, for example by evacuating fluid from the device (e.g.,using compressed air or vacuum suction) and then collapsing the devicefor removal through the small opening left when the connectors areremoved (e.g., without reopening the tissue opening). A tether can beused to pull out the collapsed device. Any remaining tissue opening canthen be closed.

In some embodiments, a thermal device having pre-attached tubing orconduits (e.g., of the type shown in FIG. 25) is placed on the targetsite (e.g., the exposed dura or spinal cord of the patient). The devicecan be placed initially while in a collapsed, rolled-up, and/or deflatedconfiguration (e.g., through a minimally-invasive pathway). If thedevice is initially placed in a collapsed configuration, fluid can bedelivered through a fluid inlet conduit to inflate the device to thedesired size or shape.

Placement of the thermal device can include conforming the device to thetarget anatomy. Placement of the thermal device can also include pullingor otherwise manipulating the pre-attached tubing or one or more tethersextending from the device to adjust a position or orientation of thedevice. Correct placement of the device can be verified visually orusing fluoroscopy or other imaging techniques. Placement of the thermaldevice can also include anchoring or clamping the device to the patientanatomy or to a device, implant, etc. at the target site (e.g., usingattachment features like those shown in FIGS. 37-41).

Thermal therapy can be applied through the device, for example bycirculating a chilled fluid through the device. The device can include areservoir filled with gel or some other substrate material, in whichcase the fluid can be circulated through the gel or substrate. Embeddedsensors can be used to monitor various parameters of the patient oroperating environment, and the thermal therapy can be modulated based onthe output of the sensors. For example, the temperature and/or flow rateof fluid circulated through the device can be adjusted to maintain adesired temperature. Where only intraoperative therapy is desired, thedevice can be removed once the desired duration of thermal therapy hasbeen applied and the tissue opening can be closed. Where postoperativetherapy is desired, the thermal device and the tubing attached theretocan be left in place and the tissue opening can be closed. The tubingcan be left exposed, extending through the closed tissue opening. Thetubing can also be left buried beneath the patient's skin, where it isreadily accessible in a minimally-invasive follow on procedure toconduct additional thermal therapy or to remove the tubing or device. Ineither case, the tubing can be sutured or otherwise secured to preventexcessive movement or inadvertent separation. Postoperative thermaltherapy can be delivered through the tubing for an extended period, asdescribed in more detail below. When the capability to deliveradditional thermal therapy is no longer desired, the tubing can beremoved. Any of the techniques described above can be used to separatethe tubing from the device, including breaking a frangible portion ofthe tubing by exerting a proximally directed pulling force, pulling atether to tear the tubing, or allowing at least a portion of the tubingto be bioabsorbed by the patient. The thermal device can be leftimplanted permanently, and can optionally be configured to bebioabsorbed by the patient over time. Alternatively, the thermal devicecan be removed, for example by evacuating fluid from the device (e.g.,using compressed air or vacuum suction) and then collapsing the devicefor removal through a small tissue opening (e.g., without reopening thetissue opening). The tubing or a tether can be used to pull out thecollapsed device. Any remaining tissue opening can then be closed.

In an exemplary method, as shown in FIGS. 46-47, a rectangular thermaldevice 102 having pre-attached inlet and outlet conduits 120, 122 can bepositioned over multiple levels of a patient's spinal column.

In some embodiments, a thermal device having a connector that can beselectively coupled or decoupled to/from a port of the thermal device(e.g., of the type shown in FIGS. 26-28) is placed on the target site(e.g., the exposed dura or spinal cord of the patient). The device canbe placed initially while in a collapsed, rolled-up, and/or deflatedconfiguration (e.g., through a minimally-invasive pathway). A connectorcan be attached to a port of the device to allow application, removal,or circulation of cooling media, before or after the device is placed atthe target site. A single connector housing inlet and exhaust conduitscan be used, or multiple connectors (e.g., one for inlet and one forexhaust) can be coupled to ports on the device. In some embodiments, asingle connector having a single conduit can be used, in which casemedia application and removal steps can be performed serially throughthe same lumen. If the device is initially placed in a collapsedconfiguration, fluid can be delivered through a fluid inlet conduit ofthe connector to inflate the device to the desired size or shape.

Placement of the thermal device can include conforming the device to thetarget anatomy. Placement of the thermal device can also include pullingor otherwise manipulating a connector coupled thereto or one or moretethers extending from the device to adjust a position or orientation ofthe device. Correct placement of the device can be verified visually orusing fluoroscopy or other imaging techniques. Placement of the thermaldevice can also include anchoring or clamping the device to the patientanatomy or to a device, implant, etc. at the target site (e.g., usingattachment features like those shown in FIGS. 37-41).

Thermal therapy can be applied through the device, for example bycirculating a chilled fluid through the device. The device can include areservoir filled with gel or some other substrate material, in whichcase the fluid can be circulated through the gel or substrate. Embeddedsensors can be used to monitor various parameters of the patient oroperating environment, and the thermal therapy can be modulated based onthe output of the sensors. For example, the temperature and/or flow rateof fluid circulated through the device can be adjusted to maintain adesired temperature. Where only intraoperative therapy is desired, thedevice can be removed once the desired duration of thermal therapy hasbeen applied and the tissue opening can be closed. Where postoperativetherapy is desired, the thermal device and the one or more connectorscoupled thereto can be left in place and the tissue opening can beclosed. The one or more connectors can be left exposed, extendingthrough the closed tissue opening. The one or more connectors can alsobe left buried beneath the patient's skin, where they are readilyaccessible in a minimally-invasive follow on procedure to conductadditional thermal therapy or to remove the one or more connectorsand/or the device. In either case, the one or more connectors can besutured or otherwise secured to prevent excessive movement orinadvertent decoupling. Postoperative thermal therapy can be deliveredthrough the one or more connectors for an extended period, as describedin more detail below. When the capability to deliver additional thermaltherapy is no longer desired, the one or more connectors can be removed.Any of the techniques described above can be used to decouple theconnectors from the device, including decoupling a snap-fit, compressionfit, or threaded connection between the connector and the device port.The thermal device can be left implanted permanently, and can optionallybe configured to be bioabsorbed by the patient over time. Alternatively,the thermal device can be removed, for example by evacuating fluid fromthe device (e.g., using compressed air or vacuum suction) and thencollapsing the device for removal through a small tissue opening (e.g.,without reopening the tissue opening). The one or more connectors or atether can be used to pull out the collapsed device. Any remainingtissue opening can then be closed.

In an exemplary method, as shown in FIG. 48, a cylindrical thermaldevice having a port on its proximal-facing end surface can bepositioned over a patient's dura after a laminectomy. The connector 116can be positioned to extend from the proximal end of the thermal deviceto a point external to the patient, where it can be coupled to thethermal source 104.

In some embodiments, a thermal device having a plurality of bendable ordeformable loops of tubing (e.g., of the type shown in FIGS. 42-45) isplaced on the target site (e.g., the exposed dura or spinal cord of thepatient). The device can be inserted initially through a tissue openingthe with tube loops bent into a longitudinally-extended position (e.g.,as shown in FIG. 44 for insertion through a minimally-invasive pathway).

Placement of the thermal device can include conforming the loops oftubing to the target anatomy, for example by bending the loops of tubingto the position shown in FIG. 45 such that a mesh of tubing is formedover the target site. Placement of the thermal device can also includepulling or otherwise manipulating a connector coupled to the loops oftubing or one or more tethers extending from the device to adjust aposition or orientation of the device. Correct placement of the devicecan be verified visually or using fluoroscopy or other imagingtechniques. Placement of the thermal device can also include anchoringor clamping the device to the patient anatomy or to a device, implant,etc. at the target site.

Thermal therapy can be applied through the device, for example bycirculating a chilled fluid through the loops of tubing. Embeddedsensors can be used to monitor various parameters of the patient oroperating environment, and the thermal therapy can be modulated based onthe output of the sensors. For example, the temperature and/or flow rateof fluid circulated through the device can be adjusted to maintain adesired temperature. Where only intraoperative therapy is desired, thedevice can be removed once the desired duration of thermal therapy hasbeen applied and the tissue opening can be closed. Where postoperativetherapy is desired, the thermal device and the one or more connectorscoupled thereto can be left in place and the tissue opening can beclosed. The one or more connectors can be left exposed, extendingthrough the closed tissue opening. The one or more connectors can alsobe left buried beneath the patient's skin, where they are readilyaccessible in a minimally-invasive follow on procedure to conductadditional thermal therapy or to remove the one or more connectorsand/or the device. In either case, the one or more connectors can besutured or otherwise secured to prevent excessive movement.Postoperative thermal therapy can be delivered through the one or moreconnectors for an extended period, as described in more detail below.When the capability to deliver additional thermal therapy is no longerdesired, the loops of tubing can be removed, for example by pulling theconnector proximally out of the patient to bend the loops of tubing intothe shape shown in FIG. 44 such that they can be withdrawn through theopening formerly occupied by the connector. Any remaining tissue openingcan then be closed. Alternatively, the thermal device can be leftimplanted permanently, and can optionally be configured to bebioabsorbed by the patient over time.

FIG. 49 illustrates a method of applying thermal therapy to tissue. Instep S200, a tissue opening is formed. A thermal device is placed at atarget site in step S202 and the tissue opening is closed in step S204.After closing the tissue opening, thermal therapy is delivered to thetarget site via the thermal device in step S206. Thermal therapy canalso be initiated or delivered via the thermal device prior to closingthe tissue opening in step S204, and can be continued or re-started instep S206 after closing the tissue opening. FIG. 50 illustrates a methodof applying thermal therapy to tissue. In step S300, a target site isaccessed. The target site is prepared in step S302, and thermal therapyis applied to the target site via a thermal device in step S304.

The thermal device can be left implanted for any amount of time (e.g.,at least about 1 hour, at least about 4 hours, at least about 12 hours,at least about 18 hours, at least about 24 hours, at least about 48hours, at least about 72 hours, at least about 5 days, at least about 7days, at least about 2 weeks, at least about 1 month, at least about 3months, at least about 6 months, at least about 1 year, at least about 5years, at least about 10 years, and/or permanently or indefinitely.

Hypothermia Delivery—Temperature & Time

The methods and devices described herein can generally involve applyinglocalized therapeutic hypothermia and, in some cases, cooling the tissuein and around the spinal cord. Various hypothermic instrumentations aredescribed to deliver a cooling effect to the spinal canal, and to thespinal cord itself. “Therapeutic hypothermia” as used herein refers tothe reduction of tissue temperature below a patient's normal bodytemperature, typically about 37 degrees C. Therapeutic hypothermia canalso include reduction of tissue temperature below a patient's bodytemperature when treatment is initiated, which may not be the patient'snormal body temperature (e.g., when the patient presents with a fever orin an already-hypothermic state, for example due to previous or ongoingsystemic hypothermia treatment).

The degree of hypothermia applied can vary upon a number of factors.Target therapeutic temperatures can range from just below 0 degrees C.to just below normothermia. Tissue exposure to temperatures below 0degrees C. can lead to cellular damage, however the bones of the spinalcolumn are relatively resilient to such low temperatures and thereforetarget therapeutic temperatures can be below 0 degrees C. in someembodiments.

In an exemplary embodiment, the target tissue is cooled to within arange of about 0 degrees C. to about 37 degrees C. The target tissue canalso be cooled to within a range of about 5 degrees C. to about 36degrees C., more preferably about 15 degrees C. to about 36 degrees C.,more preferably about 25 degrees C. to about 36 degrees C., morepreferably about 25 degrees C. to about 35 degrees C., and morepreferably about 30 degrees C. to about 34 degrees C. In certainembodiments, the target tissue can be cooled to about 36 degrees C.,about 35 degrees C., about 34 degrees C., about 33 degrees C., about 32degrees C., about 31 degrees C., or about 30 degrees C. In otheraspects, the target tissue can be cooled to about 1 degree C. belownormothermia, about 2 degrees C. below normothermia, about 5 degrees C.below normothermia, about 10 degrees C. below normothermia, or about 20degrees C. below normothermia.

Degrees of hypothermia are sometimes described in terms of “mild”hypothermia (e.g., 0-5 degrees C. below normothermia), “moderate”hypothermia (e.g., 5-9 degrees C. below normothermia), “severe”hypothermia (e.g., 9-17 degrees C. below normothermia), and “profound”hypothermia (e.g., more than 17 degrees C. below normothermia). Themethods disclosed herein can include cooling of tissue to within any ofthese ranges, and the systems and devices disclosed herein can beconfigured to achieve such cooling. Various treatment protocols can alsobe used in which the tissue temperature is cycled, pulsed, swept,ramped, and/or stepped through these or other ranges. For example, inone treatment method, the tissue temperature can be quickly lowered to atarget temperature and then slowly ramped back up to normothermia whenit is desired to cease treatment. By way of further example, the tissuetemperature can be slowly stepped down to a first target temperature,oscillated between the first target temperature and a second targettemperature, and then eventually stepped back up to normothermia.

The duration of exposure of the target tissue to the cooling effect canrange from minutes to days, weeks, months, or years depending on avariety of factors, including the patient's condition, the treatment ofthe patient's other injuries, the prospective treatment protocol for thepatient, and monitored or detectable physiological responses, or lackthereof, to the cooling. Therapeutic hypothermia can be applied in asingle procedure or multiple times. In either case, a multiplicity ofdifferent temperatures can be applied. Preferably, when discussingtarget temperatures, it is intended to mean the desired therapeutictemperature of the targeted tissue. Alternatively, target temperature attimes can also refer to the temperature of the thermal device or thecooling chamber or element of the thermal device. It will be appreciatedthat it can be necessary in some instances to cool the thermal device tobelow the target tissue temperature in order for the target tissue toreach the target tissue temperature.

The methods described herein can include cooling the spinal canal tissueand the spinal cord for variable lengths of time and/or at differenttemperatures. In addition, cooling can occur in multiple doses, whereeach dose can differ from the others in exposure time and/ortemperature. The determination of the exposure time(s) andtemperature(s) can be predetermined based on known effective times andtemperatures or can be determined based on the condition of the patientand/or when the treatment is applied relative to when the injuryoccurred. A wide variety of physiological effects, both local andsystemic, can arise from the cooling of the target tissue (e.g., spinalcanal tissue and the spinal cord) below normal body temperature.Exposure time, doses, and target temperature can be varied during theprocedure based on monitored physiological parameters or characteristicsas well as parameters of the cooling devices or systems.

These parameters include, but are not limited to, neurological findings,blood pressure, target-tissue temperature, specific tissue temperature(proximate to target tissue), core (rectal) body temperature, venousblood temperature near or exiting target tissue, pulmonary conditions,cardiac conditions, sensory evoked potentials (SEPs, includingsomatosensory evoked potentials), motor-evoked potentials (MEPs),intrathecal pressure, perfusion pressure, levels of blood oxygen &glucose, ATP concentrations, markers of excitotoxicity, vasogenic edema,apoptosis, inflammation, and enzymatic responses. The targettemperature, doses, and exposure time can be selected by initialmeasurements of these physiological parameters and then modified basedupon real-time measurement of these parameters. Effectively, the coolingregimen, in terms of temperatures, exposure times, and doses, can becontrolled by measured physiological characteristics of the patient andthe cooling devices and systems.

For example, a cooling effect can be applied initially at apredetermined target temperature based on the type and severity ofinjury incurred, including for example the vertebral level of injury.The cooling effect can be increased, and as such, the target temperaturecan be reduced, if after a predetermined period of time, themotor-evoked potential responses of the patient appear unremarkable. Inone embodiment, if the difference between the arterial blood pressureand the cerebral spinal fluid pressure reduces below a predeterminedthreshold, the application of the therapeutic hypothermia can bestopped. It should be understood that there are any number of protocolsthat can be followed in the application of therapeutic hypothermia basedon clinical, laboratory, and monitoring markers.

In one embodiment, therapeutic hypothermia is initiated as soon aspossible following a spinal injury, e.g., less than 8 hours after theinjury. Therapeutic hypothermia can be maintained up to 72 hours, up to120 hours, or more. It can be desirable to deliver therapeutichypothermia for a much shorter duration as well, including as little asa fraction of an hour (e.g., 5 minutes, 15 minutes, 30 minutes, or 45minutes).

The use of therapeutic hypothermia on the spinal cord and the spinalcanal can yield a variety of beneficial effects. Such effects caninclude the reduction of nervous tissue metabolic demand, excitotoxicmarkers, apoptosis, free-radicals, and inflammation. It should be notedthat some of the mechanisms of action associated with therapeutichypothermia are not fully understood, but experience with itsapplication in a variety of clinical situations suggests a mitigatingeffect in spinal cord damage from trauma, vascular insult, or surgicalinsult.

Transosseous Cooling

In some of the methods and devices described herein, a cooling effect isapplied transosseously, or through bone. In particular, tissue can becooled by positioning a thermal device over adjacent or nearby bone orover an implant implanted in adjacent or nearby bone. Bone hasproperties that make it an advantageous cooling platform. Boneystructures are readily locatable due to their greater density andrigidity than so-called soft tissues. Furthermore, their geometries arereadily mapped radiographically, are relatively consistent betweenpatients, and have easily locatable features or landmarks. Accordingly,particular surrounding or soft tissues are relatively consistentlylocated in a known proximity to these bone structures and landmarks. Inparticular, vertebral pedicles and lamina lie in close proximity to thecontents of the spinal canal, including the spinal cord and nerve roots.

These attributes allow specific surrounding soft tissue to be reliablytargeted by using adjacently located bone structures and landmarks ofthe bone structures as a platform and avenue to put devices near thespecific soft tissue. Using bony structures and their landmarks as ameans for targeting nearby or adjacent tissues helps avoid a need todirectly target the tissue wishing to be treated, leaving the tissueundisturbed.

An advantageous aspect of a transosseous approach for providing acooling effect to nearby soft tissue is the fact that bone is rigid,allowing for an device to be securely anchored into or on the bone,where the bone is not subject to deformation because of bodily movementor because of the device's presence. The rigid nature of the bone alsoallows a thermal device applied or anchored thereto without disturbingthe tissues outside of the bone.

A transosseous approach for providing a cooling effect to nearby softtissue allows for the implantation of thermal instrumentation withoutdisturbing the soft tissue itself. That is, by using a bone approach andcooling across the bone wall to the nearby tissue, the targeted nearbytissue is not physically touched, displaced, or incised by the thermaldevice or by the surgical steps needed to implant the thermal device.Certain tissues, such as spinal cord tissue, are delicate and sensitiveto disturbances, and such disturbances could cause permanent injury tothe tissues. As such, it can be undesirable to implant thermal devicesin these tissues or in nearby soft tissues due to risks of causinginjury to the tissues. Bone is very resilient to such disturbances, andtypically does not realize a great loss in function or strength and istypically not susceptible to long term injury from such disturbances. Itis therefore desirable to apply or affix a thermal device to a bonystructure and cool nearby soft tissue transosseously, or across the bonewall, thus allowing for reliable cooling access to soft tissue withoutphysically disturbing the soft tissue itself.

In exemplary embodiments, the soft tissue that is targeted to be cooledis the spinal cord, other spinal canal tissue, and/or nerve root tissue,and the bony structures which act as the cooling platform are parts of avertebra, including the elements of the posterior arch such as thepedicles, the lamina, and the spinous process. A transosseous approachfor providing cooling across pedicle and/or lamina bone to the adjacentspinal canal contents targets the spinal cord without its actualcontact, displacement, or penetration. This can be a criticalconsideration since the spinal cord's tolerance for such intrusions islikely minimal. In some embodiments, however, particularly those inwhich a decompression procedure is performed, the thermal devices can beplaced in direct contact with the spinal cord or the dura.

Concluding Statements

It will be understood that any of the methods and devices disclosedherein can be used on multiple vertebrae at once and/or multiple bonystructures of each vertebra at once, by utilizing multiple thermaldevices at the same time or a single, larger thermal device. It will beunderstood that the methods and devices disclosed herein can be used forconditions other than traumatic spinal cord injury, including forcooling other tissues. The methods and devices can be used for othertypes of spinal cord injury, as well as for treating nerve root damage.The methods and devices can be used prophylactically. The methods anddevices can be used before, during, and/or after an injury occurs andcan be used pre-operatively, peri-operatively, intra-operatively and/orpost-operatively with regard to any particular procedure that can beconducted.

Furthermore, the methods and devices can be used for non-injury relatedpurposes. In particular, the methods and devices described herein can beused as an adjunctive procedure to an aneurysm repair surgery, such asthoracoabdominal aortic aneurysm repair or abdominal aortic aneurysmrepair. In these procedures, it is common for blood flow to the spinalcord to be compromised, thus introducing a risk of ischemic spinal cordinjury. The methods and devices described herein can provide aprotective therapy during such ischemic periods.

Further, the methods and devices described herein can also be used forspinal fusion procedures where cooling is not initially intended. Themethods and devices described herein can be used for fusion with theunderstanding that an intraoperative complication can occur (example:iatrogenic injury caused during scoliosis correction surgery) wherehaving the capability to deliver a cooling effect can be desired.

The methods and devices described herein can be used prophylactically todeliver a cooling effect to nerve roots. Though such delivery of acooling effect can be achieved with one thermal device, it can be betterachieved by having two or more thermal devices placed above and belowthe particular root that is being targeted. The delivery of a coolingeffect to a nerve root can also occur peri-operatively orpost-operatively.

It will be appreciated that the methods and devices disclosed herein canbe used in other parts of a mammalian body, and in particular, can beused with orthopedic procedures to deliver a cooling effect tosurrounding tissues.

The described aspects above are given as illustrative examples of thosethat fall within the scope of the subject matter described, but are notintended to limit that scope. The described devices and methods can bethe sole devices and methods used and performed in the spine at the timeof the herein described therapy or can accompany other devices andprocedures such as those related to spinal decompression, reduction,stabilization, and fusion.

The devices disclosed herein can be designed to be disposed of after asingle use, or they can be designed to be used multiple times. In eithercase, however, the device can be reconditioned for reuse after at leastone use. Reconditioning can include any combination of the steps ofdisassembly of the device, followed by cleaning or replacement ofparticular pieces, and subsequent reassembly. In particular, the devicecan be disassembled, and any number of the particular pieces or parts ofthe device can be selectively replaced or removed in any combination.Upon cleaning and/or replacement of particular parts, the device can bereassembled for subsequent use either at a reconditioning facility, orby a surgical team immediately prior to a surgical procedure. Thoseskilled in the art will appreciate that reconditioning of a device canutilize a variety of techniques for disassembly, cleaning/replacement,and reassembly. Use of such techniques, and the resulting reconditioneddevice, are all within the scope of the present application.

Preferably, the devices described herein will be processed beforesurgery. First, a new or used device is obtained and if necessarycleaned. The device can then be sterilized. In one sterilizationtechnique, the device is placed in a closed and sealed container, suchas a plastic or TYVEK bag. The container and its contents are thenplaced in a field of radiation that can penetrate the container, such asgamma radiation, x-rays, or high-energy electrons. The radiation killsbacteria on the device and in the container. The sterilized device canthen be stored in the sterile container. The sealed container keeps thedevice sterile until it is opened in the medical facility.

Further details on methods and devices for cooling tissue, includingmethods and devices which can be used in conjunction with thosedescribed herein, are discussed in U.S. Pat. No. 8,523,930 issued onSep. 3, 2013, entitled “METHODS AND DEVICES FOR COOLING SPINAL TISSUE,”and U.S. application Ser. No. 13/751,503 (which is expected to issue asU.S. Pat. No. 8,721,642 on May 13, 2014), entitled “TISSUE COOLINGCLAMPS AND RELATED METHODS,” which are hereby incorporated by referenceherein in their entirety.

The foregoing description has been presented for purposes ofillustration and description. Many modifications and variations of thesubject matter described will be apparent to those skilled in the art.Although the invention has been described by reference to specificembodiments, it should be understood that numerous changes can be madewithin the spirit and scope of the inventive concepts described.Accordingly, it is intended that the invention not be limited to thedescribed embodiments, but that it have the full scope defined by thelanguage of the following claims.

The invention claimed is:
 1. A method of applying thermal therapy totissue, the method comprising: forming a tissue opening in a patient toaccess a target site within the patient, wherein the target site isspinal cord dura mater; performing a laminectomy to expose a posteriorsurface of the spinal cord dura mater; passing a thermal devicecomprising a malleable or deformable pad formed of a membrane definingan internal fluid reservoir through the tissue opening; and placing thethermal device at the target site wherein the internal fluid reservoiris in thermal contact with the target site and applying thermal therapyto the target site by placing an outer surface of the thermal deviceonto the target site.
 2. The method of claim 1, wherein the malleable ordeformable pad is resiliently or non-resiliently malleable ordeformable.
 3. The method of claim 1, wherein the membrane is configuredto form a negative of an anatomical feature against which it is placed.4. The method of claim 1, wherein the malleable or deformable pad isformed from one or more of the following: silicone, polyethyleneterephthalate (PET), nylon, polyethylene (PE), polyurethane, polyvinylchloride (PVC), latex, titanium, steel, gold, cobalt, chrome, orcombinations thereof.
 5. The method of claim 1, wherein the malleable ordeformable pad includes wings or tabs which define a thermal transfersurface and a malleable wireframe disposed therein.
 6. The method ofclaim 5, wherein the wireframe may be shaped to contour the spinal corddura mater.
 7. The method of claim 1, wherein thermal therapy is appliedto the target site through the thermal device before the tissue openingis closed.
 8. The method of claim 1, further comprising: closing thetissue opening with the thermal device at the target site; and afterclosing the tissue opening, applying or continuing to apply thermaltherapy to the target site via the thermal device.
 9. The method ofclaim 8, further comprising installing one or more spinal fixationimplants prior to closing the tissue opening.
 10. The method of claim 1,wherein the thermal device is placed on the exposed posterior surface ofthe spinal cord dura mater.
 11. The method of claim 1, wherein thethermal device comprises an insulating coating positioned on allportions of the thermal device except for a thermal transfer surfacethat is placed on the target site.
 12. The method of claim 11, whereinthe insulating coating is silicone.
 13. The method of claim 1, whereinthe internal fluid reservoir contains one or more embedded sensors. 14.The method of claim 13, wherein a temperature sensor is one of the oneor more embedded sensors.
 15. The method of claim 1, further comprisingremoving the thermal device after completion of the thermal therapy. 16.The method of claim 1, wherein the internal fluid reservoir includes athermal transfer fluid selected from the group consisting of: salinesolution, water, liquid nitrogen, ethyl alcohol, and combinationsthereof.
 17. The method of claim 1, wherein the malleable or deformablepad includes an embedded malleable wireframe disposed therein that maybe shaped to contour the spinal cord dura mater.